Pumps for Phosphoric Acid (H3PO4)
Why phosphoric acid is hard on pumps
With phosphoric acid, the grade is the duty. Food-grade acid is clean and comparatively predictable. Merchant and wet-process acid is a different fluid: it carries abrasive solids from the source rock, and the combination of corrosion and abrasion is what actually destroys pumps. Corrosion roughens a surface, abrasion strips the roughened layer, and the two accelerate each other in a way neither would alone. Heat and contamination push stainless grades that handle clean, cool acid out of their comfort zone. A pump selected for the name on the drum, rather than the grade in it, fails early.
Approaches that get specified
Solid engineered thermoplastic wetted parts suit the corrosive-abrasive combination because there is no lining to wear through and no passive layer to strip: the material is the same all the way down. For acid carrying solids, vortex and recessed impeller designs pass what a close-clearance impeller would grind against. Sealless and magnetically driven configurations remove the seal from a fluid that attacks seal faces both chemically and mechanically. Metering pumps cover phosphoric acid feed duties in water treatment and process dosing.
How RE Merrill confirms the selection
Phosphoric acid selections turn on grade, concentration, temperature, and solids content, and we confirm all four against curated compatibility data and factory guidance before we quote. Send the duty: acid grade, concentration, temperature, flow, head, and whether the service is transfer, feed, or sump, and we return a confirmed selection.
Related lines
Related reading
- Thermoplastic Pump Materials Guide: PVC, CPVC, PP, PVDF, ECTFE, and PTFE Compared
- Thermoplastic vs. Metal Pumps: Which Should You Specify?
- Plastics vs. Stainless Steel in Pharmaceutical Plants